The American Heart Association/American Stroke Association (AHA/ASA) has updated its guidelines on endovascular treatment for acute ischemic stroke — strongly recommending its use in certain patients — based on the influx of new clinical trial data that have recently become available.
The "2015 AHA/ASA Focused Update of the 2013 Guidelines for the Early Management of Patients With Acute Ischemic Stroke Regarding Endovascular Treatment" was published online June 29 in Stroke.
"We have given the strongest recommendation possible — class 1, level of evidence A — for certain stroke patients to receive endovascular treatment," lead author, William J. Powers, MD, University of North Carolina at Chapel Hill, told Medscape Medical News. "This is the first time such treatment has been strongly recommended in stroke. This is because of the new trials which show very clearly that it is beneficial in certain groups of patients."
The guidelines are based on five new clinical trials reported in the past few months: MR CLEAN, ESCAPE, EXTEND-IA, SWIFT-PRIME, and REVASCAT.
Dr Powers noted that that the guidelines specifically recommend that stent retrievers should be used if possible for the endovascular treatment. "This is what was used mainly in the new positive trials and they do seem to give better reperfusion of the brain faster."
On the matter of imaging, the guidelines advise the simple strategy of just confirming the presence of a clot in a major artery and using noninvasive computed tomography to assess whether there is salvageable brain tissue (Alberta Stroke Program Early CT [ASPECT] score > 6).
"We can only make recommendations on what has been shown," he said. "Pretty much all the trials selected patients with an ASPECT score >6. Only one trial (MR CLEAN) included patients with lower scores and there weren't many, and the intervention didn't seem very effective in this group."
He added: "Some of the trials used various sophisticated imaging to identify patients who would benefit most, but they all used different systems and some patients may be excluded who would benefit if these more sophisticated systems were used. So we felt it was impossible to recommend anything but the simplest imaging modalities that identify the clot and show evidence of salvageable brain. We can't know if anything more complicated is better at the moment."
But the guidelines emphasize that thrombolysis should be given before vascular imaging is performed.
Dr Powers said there were three bottom-line messages:
None of these new results changes the fact that patients suspected of having had a stroke need to get to a primary stroke center fast so they can be given tissue plasminogen activator (tPA). This is still the first-line therapy for acute ischemic stroke.
All patients who fit the criteria for endovascular therapy should be considered for this treatment in addition to receiving tPA. If patients are in the eligible group they should be taken to a comprehensive stroke center, where endovascular treatment can be performed.
Systems of care, such as a hub-and-spoke model, for acute ischemic stroke need to be put in place so that eligible patients can be quickly transported to the comprehensive centers for endovascular treatment.
Criteria for Eligibility
The guidelines state that patients should receive endovascular therapy with a stent retriever if they meet all the following criteria (class i; level of evidence A):
Prestroke modified Rankin Scale (mRS) score 0 to 1;
Acute ischemic stroke with receipt of intravenous recombinant tPA within 4.5 hours of onset;
Causative occlusion of the internal carotid artery or proximal (M1) middle cerebral artery (MCA);
Age 18 years or older;
National Institutes of Health Stroke Scale (NIHSS) score of 6 or greater;
ASPECT score of 6 or greater; and
Treatment that can be initiated (groin puncture) within 6 hours of symptom onset.
Other recommendations include the following:
Reperfusion should be achieved as early as possible, and when treatment is initiated beyond 6 hours from symptom onset, the effectiveness of endovascular therapy is uncertain.
In carefully selected patients with anterior circulation occlusion who have contraindications to tPA, endovascular therapy is reasonable. Intra-arterial fibrinolysis initiated within 6 hours of stroke onset in carefully selected patients who have contraindications to the use of intravenous tPA might be considered, but the consequences are unknown.
Endovascular therapy "may be reasonable (although benefits are uncertain)" for carefully selected patients who have causative occlusion of the M2 or M3 portion of the MCAs, anterior cerebral arteries, vertebral arteries, basilar artery, or posterior cerebral arteries; for some patients younger than 18 years of age; for those who have prestroke mRS score of greater than 1, ASPECT score less than 6, or NIHSS score less than 6.
Observing patients after tPA administration to assess for clinical response before pursuing endovascular therapy is not required and is not recommended.
The use of proximal balloon guide catheter or a large-bore distal access catheter rather than a cervical guide catheter alone in conjunction with stent retrievers may be beneficial, and the use of salvage technical adjuncts, including intra-arterial fibrinolysis, may be reasonable to achieve thrombolysis in cerebral infarction 2b/3 angiographic results.
It might be reasonable to favor conscious sedation over general anesthesia during endovascular therapy for acute ischemic stroke. However, the ultimate selection of anesthetic technique during endovascular therapy for acute ischemic stroke should be individualized on the basis of patient risk factors, tolerance of the procedure, and other clinical characteristics.
Stroke. Published online June 29, 2015. Abstract